The ability to perform endoscopic tissue imaging using a fiber-coupled two-photon laser has recently been demonstrated by several research groups. For many applications the size of the scanning mechanism for image creation is a limiting factor in system miniaturization. Many projects concentrate on automated x- and y-scanning, but a fast enough scanning mechanism parallel to the optical path could ultimately lead to 3-dimensional imaging of tissue structures in vivo, with novel diagnostic capabilities for allergic diseases and cancer.